Aplicação da bentonita de Melo com diferentes granulometrias no desenvolvimento de formulações cosméticas capilares veganas

Abstract

Clay minerals may have interesting properties for application in the field of cosmetology, due to their high ion exchange capacity, small particle size and mineralogical composition. Melo bentonite is a smectite belonging to the phyllosilicate group, it was extracted from a deposit in the municipality of Melo (UY). Among the lines that make up cosmetology, the hair line is interested in the incorporation of clay as an active, because when clay is applied to the scalp it provides benefits such as removal of dead cells, absorption of impurities and activation and improvement of blood circulation. Natural and vegan products are a trend in cosmetology. In this perspective, the present work develops vegan hair cosmetic formulations, whose main asset is the bentonite clay of Melo. The Melo bentonite is subjected to the decontamination process and sample characterization by microbiological analysis, granulometric distribution, X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), surface area evaluation and scanning electron microscopy (SEM). Fractions ≤ 45 µm and ≤ 180 µm were selected for the preparation of vegan hair formulations, which have, in addition to Melo bentonite: water, cetostearyl alcohol, 50% cetyl trimethyl ammonium chloride, preservative, vegetable glycerin, polyquaternium 7, almond oil and 20% citric acid solution. The formulations were stored under the following conditions: oven (45 ± 2°C), refrigerator (2 ± 2°C) and room temperature (20 ± 2°C). During the tests, the organoleptic characteristics, pH, spreadability and viscosity were evaluated in the formulations. The formulation containing ≤ 180 µm was submitted for assessment of potential for primary and accumulated irritation and skin sensitization in vivo. From X-ray diffraction (XRD) the presence of the smectite and quartz group in the sample is verified. The surface area of the Melo bentonite sample with particle size ≤ 45 µm is 35.003 m²/g and that with particle size ≤180 µm is 10.673 m²/g. The viscosity and spreadability of the formulations were influenced by the storage condition and the formulations showed maximum average spreadability, regardless of the exposure condition, around 1500 mm2. From the viscosity results, the formulations were classified as pseudoplastic with non-Newtonian behavior. The formulation containing particle size ≤ 180 µm remained stable throughout the study and presents microbiological evaluation in accordance with accepted microbiological parameters. The dermal irritability test, accumulated dermal irritability and in vivo dermal sensitization was performed on the formulation with the best results, that is, with granulometry ≤ 180 µm, and proved the absence of the potential for primary, accumulated skin irritability and sensitization of the formulation. The application of Melo bentonite in cosmetic products presents positive perspectives. [resumo fornecido pelo autor]